Question

When is virtual image formed by a concave mirror of focal length 20 cm ? Draw its ray diagram ....​

Answer 1

Answer:

see diagram as shown in figure, here you can see position of object , position of image and and complete ray diagram.

given, focal length of concave mirror, f = -20 cm

distance of object from the mirror, u = -10 cm

use formula, 1/v + 1/u = 1/f

or, 1/v = 1/f - 1/u

or, 1/v = 1/-20 - 1/-10

or, 1/v = -1/20 + 1/10 = 1/20

or, v = +20cm

hence, image position is 20cm right side from the pole of concave mirror as shown in diagram.

Explanation: